Compact recliner assembly for a vehicle seat

ABSTRACT

A recliner assembly for selectively locking a seat back in one of a plurality of reclined positions relative to a seat cushion on a vehicle seat. The recliner includes a cylindrical shaft extending axially and longitudinally between first and second ends and having a plurality of teeth extending radially outwardly therefrom between the first and second ends. The recliner also includes a seat back disc rotatably coupled to the shaft between the teeth and the first end and fixedly secured to the seat back and having a rack of teeth extending axially therefrom. The recliner includes a seat cushion disc fixedly secured to the shaft between the seat back disc and the first end and also fixedly secured to the seat cushion. A locking disc having a center bore defined by a plurality of locking teeth is axially coupled to the shaft by mating engagement of the locking teeth with the teeth on the shaft. A cam ring is slidably coupled to the shaft and fixedly secured to the locking disc. The cam ring has a plurality of ramped cam surfaces extending axially toward the second end of the shaft. A cam disc is rotatably coupled to the shaft between the cam ring and the second end and has a plurality of cam blocks extending axially toward the cam ring for engagement therewith. Upon rotation of the cam disc about the shaft, the cam blocks engage with the cam surfaces and force the cam ring and the locking disc to move axially along the shaft to lockingly engage the locking teeth with the teeth on the seat back disc for selectively locking said seat back in one of the reclined positions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention relates to a recliner assembly for adjustment of aseat back relative to a seat cushion of an automotive vehicle seat.

2. Description of the Prior Art

Automotive vehicles include vehicle seat assemblies for supporting aseated occupant in the vehicle. The seat assemblies typically comprise agenerally horizontal seat cushion and a seat back pivotally connected tothe seat cushion by a recliner mechanism allowing adjustment of the seatback relative to the seat cushion between a plurality of reclinepositions. Each of the seat cushion and the seat back commonly comprisea rigid frame structure supporting a cellular foam pad that is encasedby a fabric trim cover.

Disc recliners are well known in the vehicle seating art and commonlyused to pivotally connect a seat back to a seat cushion. Disc reclinerscommonly include a cylindrical inner disc fixedly secured to the seatcushion and a cylindrical outer disc fixedly secured to the seat backand rotatably coupled to the inner disc. Disc recliners further includea locking mechanism for maintaining the angular position of the seatback relative to the seat cushion. The locking mechanism typicallycomprises a rack of teeth on the outer disc and several pawls each witha plurality of teeth. The pawls are moveable in a radial directionbetween a locked position and an unlocked position. With the pawls inthe locked position, the teeth on the pawls are interlocked with therack of teeth on the outer disc, thus locking the angular position ofthe seat back relative to the seat cushion. When the pawls are movedfrom the locked position to the unlocked position, the teeth on thepawls are no longer interlocked with the rack of teeth on the outerdisc, thus allowing adjustment of the seat back relative to the seatcushion.

SUMMARY OF THE INVENTION

This invention relates to a recliner assembly having a locking mechanismthat is operable in an axial direction so as to minimize the packagesize of the recliner assembly. The recliner assembly comprises acylindrical shaft extending longitudinally between opposite first andsecond ends. The shaft has an outer surface and a plurality of shaftteeth extending radially outwardly from the outer surface between thefirst and second ends. The recliner further includes a seat back discrotatably journaled to the shaft between the shaft teeth and the firstend and adapted to be fixedly secured to the seat back. The seat backdisc has opposite first and second surfaces substantially parallel tothe first and second ends of the shaft, respectively, and a plurality offirst locking teeth extending axially from one of the first and secondsurfaces. A seat cushion disc is fixedly secured to the shaft betweenthe seat back disc and the first end and is adapted to be fixedlysecured to the seat cushion. A locking disc having a center bore definedby a plurality of inner teeth is axially coupled to the shaft by matingengagement of the inner teeth with the shaft teeth. The locking disc hasopposite first and second surfaces substantially parallel to the ends ofthe shaft, respectively, and a plurality of second locking teethextending axially from one of the first and second surfaces. A cam ringis slidably coupled to the shaft and fixedly secured to the lockingdisc. The cam ring has at least one ramped cam surface extending axiallytoward the second end of the shaft. The recliner also includes a camdisc rotatably journaled to the shaft between the cam ring and thesecond end. The cam disc has at least one cam block extending axiallytoward the cam ring for engagement therewith whereby the cam blockengages the cam surface and forces the cam ring and the locking disc tomove axially along the shaft to lockingly engage the first locking teethwith the second locking teeth in response to rotation of the cam discabout the shaft for selectively locking the seat back in one of thereclined positions.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a schematic side view of an automotive seat assemblyincorporating the subject invention;

FIG. 2 is a perspective exploded view of a recliner assembly accordingto the subject invention;

FIG. 3 is a cross-sectional view of the recliner assembly of the subjectinvention shown in a locked position;

FIG. 4 is a cross-sectional view of the recliner assembly of the subjectinvention shown in an unlocked position;

FIG. 5 is a perspective view of a cam disc of the recliner assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A seat assembly for use in an automotive vehicle is generally shown at10 in FIG. 1. The seat assembly 10 includes a seat cushion 11 and a seatback 12. Each of the seat cushion 11 and the seat back 12 includes arigid frame structure that supports a contoured, foam pad encased by atrim cover. A recliner assembly 13 presenting a pivot axis A operativelyinterconnects the seat cushion 11 and seat back 12 for pivotal movementof the seat back 12 about a pivot axis A between one of a plurality ofreclined seating positions, shown between B and C in FIG. 1 and aforwardly folded flat position, shown at D in FIG. 1. Further, the seatback 12 is continuously biased to the forwardly folded flat position Dby a coil spring (not shown) attached between the seat back and the seatcushion 11.

Referring to FIG. 2, the recliner assembly 13 comprises a shaft 14having a first end 15 and a second end 16. The shaft 14 presentsdefining a longitudinal axis, which defines the pivot axis A. The shaft14 includes a mounting surface 17 adjacent to the first end 15 of theshaft 14 for receiving a fixed flange or seat cushion disc 22. The shaft14 further includes a first bearing surface 18 adjacent to the mountingsurface 17 for receiving a mobile flange or seat back disc 23. The shaft14 further includes a second bearing surface 19 adjacent to the firstbearing surface 18 for receiving a locking member or locking disc 24.The second bearing surface 19 has a plurality of shaft teeth 20 whichextend radially therefrom. The shaft 14 further includes a third bearingsurface 21 adjacent to the second bearing surface 19 for receiving a cammember or cam disc 25. Described further below, a cam ring 50 ispositioned between the cam disc 25 and the locking disc 24. The seatcushion disc 22, the seat back disc 23, the locking disc 24, the camring 50, and the cam disc 25 each have a first surface 26 substantiallyparallel to the first end 15 of shaft 3, a second surface 27substantially parallel to the second end 16 of shaft 3; an outerperipheral surface 28 interconnecting the first surface 26 and thesecond surface 27; and a center bore 29 defined by an inner surface 30extending between the respective first surface 26 and the second surface27 for receiving the shaft 14 therethrough.

The seat cushion disc 22 is fixedly attached to the mounting surface 17of the shaft 14 by any suitable methods such as by a press fit or keyedrelationship between the center bore 29 of the seat cushion disc 22 andthe mounting surface 17 of the shaft 14. The seat cushion disc 22includes a lip 33 extending from the second surface 27 of the seatcushion disc 22. Further, the seat cushion disc 22 is fixedly attachedto the seat cushion 11 by any suitable means, such as by being bolted orwelded to a portion of the frame of the seat cushion 11, as shown at Ein FIGS. 3 and 4. Thus, the shaft 14 is fixed relative to the seatcushion 11.

The seat back disc 23 is rotatably mounted to the shaft 14 on the firstbearing surface 18 and a portion of the seat back disc 23 is spacedaxially relative to the seat cushion disc 22 by contact between thefirst surface 26 of the seat back disc 23 and a lip 33 on the secondsurface 27 of the seat cushion disc 22, as best shown in FIG. 3. Theseat back disc 23 is fixedly attached by any suitable means to the seatback 12, such as by being bolted or welded to a portion of the frame ofthe seat back 12 as shown at B in FIGS. 3 and 4. The seat back disc 23includes a plurality of first locking teeth 35 projecting from itssecond surface 27. The second surface 27 of the seat back 23 furtherincludes an annular surface 66. The annular surface 6 includes a steppedannular recess 36 having first and second ends 67, 68 which define therange of reclined seating positions, shown between B and C in FIG. 1. Asexplained in detail below, the first end 67 defines a default,forward-most reclined seating position C for the seat back 12.

The locking disc 24 is assembled to the shaft 14 on the second bearingsurface 19. The locking disc 24 includes a plurality of inner teeth 38extending radially from its inner surface 30. The locking disc 24 isrotatably constrained by complementary engagement of the inner teeth 38of the locking disc 24 with the shaft teeth 20. By this arrangement, thelocking disc 24 can move axially along the shaft 14 between a lockedposition towards the seat back disc 23, as shown in FIG. 3, and anunlocked position away from the seat back disc 23, as shown in FIG. 4.The locking disc 24 is biased to the unlocked position by use of aspring 39 positioned between the locking disc 24 and the seat back disc23. The locking disc 24 includes a plurality of second locking teeth 40extending from its first surface 26 for locking engagement with thefirst locking teeth 35 of the seat back disc 23. The locking disc 24further includes a tab 41 for sliding engagement with the annular recess36 and the annular surface 66 of the seat back disc 23. A hole 52 isformed in the second surface of the locking disc 24, the purpose ofwhich is described below.

The cam disc 25 is rotatably assembled and axially constrained to thesecond end 16 of the shaft 14 on the third bearing surface 21 formovement between a released position and an unreleased position. As bestshown in FIG. 5, a cylindrical portion 43 extends from the first surface26 of the cam disc 25 defining an outer bearing surface 44 that isparallel to the inner surface 30 of the cam disc 25 and interconnects aseries of cam blocks 45 extending from the first surface 26. Each of thecam blocks 45 are defined by a leading edge 46, the outer bearingsurface 44, a trailing edge 47, and the outer peripheral surface 28. Thecam disc 25 further includes a hole 48 in the outer peripheral surface28 for fixedly receiving a release handle 49.

The cam ring 50 is located between the cam disc 25 and locking disc 24.The cam ring 50 is rotatably constrained by a pin 51 extending from thefirst surface 26 of the cam ring 50 into a hole 52 in the second surface27 of the locking disc 24. Referring back to FIG. 1, the cam ring 50further includes a series of cam surfaces 53 extending from its secondsurface 27, corresponding in number and position to the cam blocks 45 onthe cam disc 25. Each cam surface 53 includes an inclined ramp surface54 for sliding engagement with the leading edges 46 of the cam disc 25.Additionally, each cam surface 53 includes a locking surface 55 whichrest against the raised surface 45 of the cam disc 25 when the cam disc25 is in the unreleased position. The cam disc 25 is rotatably engagedwith the cam ring 50 by insertion of the cylindrical portion 43 throughthe center bore 29 of the cam ring 50. As explained in detail below,rotation of the cam disc 25 between the unreleased position and thereleased position results in axial motion of the cam ring 50 and thelocking disc 24 between the locked position against the seat back disc23, as shown in FIG. 3, and the unlocked position away from the seatback disc 23, as shown in FIG. 4.

A return spring 56, having a first end 57 and a second end 59, ismounted to the second end 16 of the shaft 14 by insertion of the firstend 57 into a slot 58 formed in the shaft 14. The return spring 56 istensioned by insertion of the second end 59 into a slot 60 on the camdisc 25, thereby biasing the cam disc 25 to the unreleased position.

As best shown in FIGS. 3 and 4, a cup shaped housing nestinglyencompasses the cam disc 25, the cam ring 50, the locking disc 24, andthe spring 39. The housing 61 is fixedly attached to the cam disc 25 byany conventional means, such as by bolting or welding. By thisarrangement, the housing 61 rotates with the cam disc 25. The housing 61further includes a hole 65 which aligns with the hole 48 in theperipheral surface 28 of cam disc 25, thus allowing assembly of therelease handle 49 through the housing 61 and into the cam disc 25.

In operation, the cam disc 25 of the recliner assembly 13 is biased bythe return spring 56 in the unreleased position, where in the unreleasedposition locking surfaces 55 of the cam ring 50, rest against the camblocks 45 of the cam disc 25 so as to hold the cam ring 50 toward theseat back disc 23. In this state, the second locking teeth 40 of thelocking disc 24 are held in locking engagement with the first lockingteeth 35 of the seat back disc 23. Further, the spring 39 is held incompression between the locking disc 24 and the cam ring 50, and the camring 50 and the cam disc 25. With the second locking teeth 40 of thelocking disc 24 in locking engagement with the first locking teeth 35 ofthe seat back disc 23, the angular position of the seat back 12 relativeto the seat cushion 11 is maintained.

To incrementally adjust the angle of the seat back 12 relative to theseat cushion 11, the cam disc 25 is rotated to the released position.Specifically, the cam disc 25 is rotated by applying a force to therelease handle 49, against the bias of the return spring 56, such thatthe cam blocks 45 of the cam disc 25 slide along the locking surfaces 55of the cam ring 50. Release of the recliner assembly 13 occurs when thecam blocks 45 and the locking surfaces 55 are no longer in contact andthe leading edges 46 of the cam disc 25 slide down the inclined rampsurfaces 54 of the cam ring 50 causing the cam ring 50 to move towardsthe cam disc 25 and away from the seat back disc 23. Following themotion of the cam ring 50, the locking disc 24 moves to the unlockedposition away from the seat back disc 23. In this state, the secondlocking teeth 40 of the locking disc 24 are no longer in lockingengagement with the first locking teeth 35 of the seat back disc 23.Once the second locking teeth 40 of the locking disc 24 has moved out oflocking engagement with the first locking teeth 35 of the seat back disc23, the angle of the seat back 12 may be adjusted relative to the seatcushion 11. As the angle of the seat back 12 is adjusted through therange of reclined seating positions between B and C, the tab 41 of thelocking disc 24 slides within the annular recess 36.

Once the angle of the seat back 12 has been adjusted to a desiredseating position, the cam disc 25 is allowed to return to the unreleasedposition. Specifically, the force applied to the release handle 49 isremoved. The return spring 56 urges the cam disc 25 into rotation suchthat the leading edges 46 of the cam disc 25 slide up the inclined rampsurfaces 54 of the cam ring 50 forcing the cam ring 50 and the lockingdisc 24 to move towards the seat back disc 12. As rotation of the camdisc 25 continues, the cam blocks 45 of the cam disc 25 eventually makecontact with the locking surfaces 55 of the cam ring 50, holding thelocking disc 24 in the locked position against the seat back disc. Withthe locking disc 24 returned to the locked position, the second lockingteeth 40 of the locking disc 24 re-engage the first locking teeth 35 ofthe seat back disc 23 and the angular position of the seat back 12relative to the seat cushion 11 is maintained.

To allow the seat back 12 to move to the biased, forwardly folded flatposition D, the cam disc 25 of the recliner assembly 13 is rotated tothe released position by applying force to the release handle 49. Oncethe locking disc 24 is disengaged from the seat back disc 23, the seatback 12 is free to pivot towards the biased, forwardly folded flatposition D. As the seat back 12 pivots, the tab 41 of the locking disceventually slides beyond the first end 67 of the annular recess 36. Oncethe tab 41 has moved beyond the first end 67 of the annular recess 36,the force applied to the released handle 49 to hold the cam disc 25 inthe released position may then be removed, allowing the tab 41 to restagainst and slide along the annular surface 36. While the tab 41 slidesalong the annular surface 36, the locking disc is held in the unlockedposition away from the seat back disc 23. Further, the cam disc 25 isheld in the unreleased position against the force of the return spring56 as the leading edge 46 of the cam disc 25 rests against the inclinedramped surface 54 of the cam ring 50. Thus, once the tab 41 has movedbeyond the first end 67 of the annular recess 36 and onto the annularsurface 36, it is no longer necessary to hold the cam disc 25 in theunreleased position with force applied to the release handle 49, and theseat back 12 can continue to pivot towards the biased, forwardly foldedflat position D.

The seat back 12 may be returned from the forwardly folded flat positionD to the default recline seating position by applying a rearward forceto the seat back 12 against the forward bias of the coil spring (notshown). As the seat back 12 is moved rearwardly from the forwardlyfolded flat position D, the tab 41 of the locking disc 24 slides alongthe annular surface 36. Once the tab 41 moves beyond the annular surface66, the return spring 56 is allowed to force rotation of the cam disc 25to the unreleased position. Rotation of the cam disc 25 to unreleasedposition forces the cam ring 50, moves to the locked position againstthe seat back disc 23. As the locking disc 24 moves to the lockedposition, the tab 41 of the locking disc 24 falls into the first end 67of the annular recess 36 of the seat back disc 23, thereby locking theseat back disc 12 in the default forward-most reclined seating positionC. In this state, the seat back 12 may again be adjusted between aplurality of reclined seating positions or the forwardly folded flatposition D.

It is should be appreciated that the seat assembly 10 may utilize morethan one recliner assembly 13 for operatively interconnecting the seatcushion 11 and the seat back 12. When more than one recliner assembly 13is used, each shaft 14 of each recliner assembly 13 preferably includesan axial bore 69 extending through and between the first and second ends15, 16. Under this configuration, a torque rod 70, as shown in FIG. 3,is inserted through and rotatably supported within each of the axialbores 69 for generally synchronous release of each of the reclinerassemblies 13 from its locked state. Alternatively, a cable may be usedto generally synchronize the rotary motions of the cam discs 25 of eachrecliner assembly 13.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology, which has been used, is intended tobe in the nature of words of description rather than of limitation.

Many modification and variations of the present invention are possiblein light of the above teachings. It is, therefore, to be understood thatwithin the scope of the appended claims, the invention may be practicedother than as specifically described.

What is claimed is:
 1. A recliner assembly for locking a seat back inone of a plurality of reclined positions relative to a seat cushion on avehicle seat, said recliner assembly comprising: a shaft extendinglongitudinally between first and second ends to define a pivot axis,said shaft having a plurality of radially extending shaft teeth; a fixedflange fixedly secured to said shaft; a mobile flange rotatablyjournaled to said shaft having a toothing extending axially outwardlytherefrom; a locking member slidably assembled to said shaft adjacentsaid mobile flange and including a plurality of radially extending innerteeth meshed with said shaft teeth for providing sliding axial movementof said locking member along said shaft relative to said mobile flange,said locking member including a toothing extending axially outwardlytherefrom for selectively and lockingly engaging said toothing of saidmobile flange; a cam member rotatably assembled to said shaft adjacentand operatively coupled to said locking member for axially displacingsaid locking member along said shaft relative to said mobile flange inresponse to rotation of said cam member, whereby said toothing of saidlocking member is selectively moveable between locking engagement withsaid toothing of said mobile flange to prevent rotation of said mobileflange relative to said shaft and out of locking engagement with saidtoothing of said mobile flange to allow rotation of said mobile flangerelative to said shaft; and a cam ring rotatably constrained againstsaid locking member and compressed between said cam member and saidlocking member, said cam ring including a raised portion extendingaxially towards said cam member for cooperating with a raised portionextending axially from said cam member to selectively control movementof said locking member axially along said shaft into said lockingengagement with said mobile flange in response to rotation of said cammember.
 2. A recliner assembly as set forth in claim 1 wherein said camring includes a locking surface extending axially towards said cammember and said cam member includes a complementary cam block forengaging said locking sufaceof said locking member, whereby saidtoothing of said locking member is held in locking engagement with saidtoothing of said mobile flange to prevent rotation of said mobile flangerelative to said shaft defining a locked state.
 3. A recliner assemblyas set forth in claim 2 wherein said cam ring member includes a rampedsurface adjacent said locking surface for engaging said cam block ofsaid cam member during rotation of said cam member, whereby said lockingmember is displaced axially relative to said mobile flange by saidrotation of said cam member.
 4. A recliner assembly as set forth inclaim 3 including a first biasing member for axially biasing saidlocking member away from said mobile flange.
 5. A recliner assembly asset forth in claim 4 including a second biasing member extending betweensaid cam member and said shaft for rotatably biasing said cam membersuch that said locking member is held in said locked state.
 6. Arecliner assembly as set forth in claim 5 wherein said second biasingmember is adapted to overcome axial bias of said first biasing member.7. A recliner assembly as set forth in claim 6 wherein said firstbiasing member spans axially between said locking member and said mobileflange and comprises spaced apart helical coils extending therebetween.8. A recliner assembly as set forth in claim 7 having an arm extendingradially outwardly from said cam member for rotatably actuating said cammember.
 9. A recliner assembly as set forth in claim 8 wherein saidfixed flange is fixedly secured to the seat cushion and said mobileflange is fixedly secured to the seat back.
 10. A recliner assembly asset forth in claim 1 wherein said locking member includes a keyedaperture for receiving a complementary portion of said shafttherethrough, whereby said locking member is rotatably constrained andaxially moveable relative to said mobile flange.
 11. A recliner assemblyas set forth in claim 10 wherein said toothing of said mobile flangecomprises an annular rack of axially extending teeth.
 12. A reclinerassembly as set forth in claim 11 wherein said toothing of said lockingmember comprises at least one tooth adapted for lockingly engaging saidannular rack of axially extending teeth of said mobile flange.